Research

This summer's research concentration focused on two seemingly dissimilar topics linked by two realities: (a) they were specifically done in the hopes that they could facilitate nanotechnology concept inclusion into high school curriculum and (b) they both were linked by the sun's link to energy -- man-made solar energy and photosynthesis. The specific research focused on how to characterize solar cell efficiency and creating microfluidics-based experimentation on algae phototaxis. Research was conducted with Dr. Michael Mauk in Drexel University's Goodwin School of Technology and Professional Studies.

Solar Cell Examination:

**Background:Solar cells commonly made of silicon, which absorbs between 400 nm and 1100 nm, As light is absorbed, electrons are knocked free within solar cells, allowing for energy production. Surface roughness of silicon a determining factor in light absorption efficiency because it can reduce the amount of light reflected from the solar cell surface.

**Problem:Since profilometry (using a stylus with a diamond tip that comes into direct contact with sample) and laser light scattering are time consuming processes for determining surface roughness, a more efficient method is desired.

**Hypothesis:Since histograms of digital photographs can be quickly produced by readily available software, it is hypothesized that their data can be just as good at determining surface roughness as more established techniques.

**Results:Using standard deviations within histograms of red spectrum data (620 nm to 750 nm), there was a correlation of the standard deviations to profilometric derived surface roughness data. Laser light scattering data did not match up with stylus findings or correlate to standard deviations. Further testing with greater amounts of samples and more refined data acquisition (especially with the laser light scattering and histograms) are needed.

Algae Microfluidics Lab-on-a-chip:

**Background: Microfluidics lab-on-a-chip is the miniaturization of experiments to a "micro" chip. Currently this has applications in biology, physics, medicine, engineering, and chemistry. Algae are photosynthetic protists that can exhibit phototaxis -- movement in response to light.

**Problem:How would algae (Euglena specifically in this experiment) respond to the production of specific light wavelengths produced by LEDs?

**Hyptothesis:If presented with red, green, and yellow LEDs, Euglena would to the red light more often. If presented with a red or green LED and no other light source, algae would end up being more highly concentrated near the LED than areas without LEDs.

**Results:Euglena moved more often to non LED areas in the first experiment to a slight extent. The second experiment showed Euglena clearly moving after being in the dark except for the LED from a concentrated distribution in each microfluidic chambers to slightly higher concentrations in the LED ports. Clumps of Euglena in all chambers were apparent after the darkness as well, which was not seen beforehand. Further experimentation with more streamlined methods is necessary; this will hopefully happen in the classroom.